Do doctors understand test results?

In 1992, shortly after Gerd Gigerenzer moved to Chicago, he took his six-year-old daughter to the dentist. She didn’t have toothache, but he thought it was about time she got acquainted with the routine of sitting in the big reclining chair and being prodded with pointy objects.

The clinic had other ideas. “The dentist wanted to X-ray her,” Gigerenzer recalls. “I told first the nurse, and then him, that she had no pains and I wanted him to do a clinical examination, not an X-ray.” These words went down as well as a gulp of dental mouthwash. The dentist argued that he might miss something if he didn’t perform an X-ray, and Gigerenzer would be responsible.

But the advice of the US Food and Drug Administration is not to use X-rays to screen for problems before a regular examination. Gigerenzer asked him: “Could you please tell me what’s known about the potential harms of dental X-rays for children? For instance, thyroid and brain cancer? Or give me a reference so I can check the evidence?” The dentist stared at him blankly.

But it’s not just that doctors and dentists can’t reel off the relevant stats for every treatment option. Gigerenzer, director of the Harding Center for Risk Literacy in Berlin, is an expert in uncertainty and decision-making. His new book, Risk Savvy, takes aim at health professionals for not giving patients the information they need to make choices about healthcare.